Solar flares are periods of increased solar activity, and are associated with geomagnetic storms, solar radiation storms, and radio blackouts that are experienced here on Earth. Neutrinos are sub-atomic particles that are generated by the Sun, and it has been speculated that the increased activity associated with solar flares can produce a short-term change in the neutrino flux detected on Earth. Detecting flare neutrinos may lead to a deeper insight into the mechanisms underlying flares, and may have practical consequences.
To date, there appears to be little if any compelling experimental evidence of an association between neutrino flux and solar flares, and this is due in part to the relatively low neutrino counting rates available from even the largest conventional detectors. The first observation and measurement of solar neutrino flux used a chlorine detector in the Homestake Gold Mine in South Dakota. The detector was a single tank containing 615 tons of tetrachloroethylene. The GALLEX detector is located at the Gran Sasso Underground Laboratories in Italy. The GALLEX detector senses solar neutrinos using a 100 ton gallium chloride target solution. A 50 kton imaging water Cerenkov detector, known as the Super Kamioka Nucleon Decay Experiment detector, has been used in Japan.